Study of magnetoresistance in Mn layer-doped Co/Cu/Co multilayers

To obtain a lower saturation/switching magnetic field in giant magnetoresistance (GMR) in Co/Cu/Co structures, a thin Mn layer was inserted into the Cu spacer at different positions. The magnetic properties and GMR effect were investigated and compared with previous results for bulk-doped Co/Cu₉₂Mn₈/Co sandwiches. It was shown that a low saturation/switching field behaviour of the GMR effect could also be caused by Mn layer doping, but starting at a much greater spacer thickness than in the bulk-doped case. This was due to the effect of different coercivities of two Co layers being dominant when the interlayer coupling between magnetic Co layers had probably been weakened enough by a Mn layer inserted beyond a certain thickness of Cu spacer. Furthermore the effects were not very sensitive to the positions of the Mn layer.